XXXVIII. (111) Let this then be premised, as of necessity it must, respecting the honourable qualities which this diagram or square has, and the name to which it is entitled, and the number seven unfolds an equal number of ideas, and even more in the case of incorporeal things, which are perceptible only by the intellect; and its nature extends also over every visible essence, reaching to both heaven and earth, which are the boundaries of every thing. For what portion of all the things on earth is there which is not fond of seven; being subdued by an affection and longing for the seventh. (112) Accordingly men say, that the heaven is girdled with seven circles, the names of which are as follows; the arctic, the antarctic, the summer tropic, the winter tropic, the equinoctial, the zodiac, and last of all the galaxy. For the horizon is something which affects ourselves, in proportion as any one has acute vision, or the contrary; our sensation cutting off at one time a lesser, and at another time a greater circumference. (113) The planets too, and the corresponding host of fixed stars, are arrayed in seven divisions, displaying a very great sympathy with the air and the earth. For they turn the air towards the times, that are called the seasons of the year, causing in each of them innumerable changes by calm weather, and pleasant breezes, and clouds, and irresistible blasts of wind. And again, they make rivers to overflow and to subside, and turn plains into lakes; and again, on the contrary, they dry up the waters: they also cause the alterations of the seas, when they receded, and return with a reflux. For at times, when the tide recedes on a sudden, an extensive line of shore occupies what is usually a wide gulf of sea; and in a short time afterwards, the waters are brought back, and there appears a sea, sailed over, not by shallow boats, but by ships of exceeding great burden. And they also give increase and perfection to all the terrestrial animals and plants which produce fruit, endowing each with a nature to last a long time, so that new plants may flourish and come to maturity; �the old ones having passed away, in order to provide an abundant supply of necessary things.